The present invention relates to a device for dispensing a fluid, and more particularly a device for spraying a solution made up of a liquid and a powder that are mixed together at the last moment by the patient.
The invention relates more particularly to devices for dispensing a small number of doses, and preferably single-dose devices or two-dose devices.
Certain substances, and more particularly pharmaceuticals, can be highly unstable in solution over time and/or can require special storage conditions which can be awkward. In particular, they can be subject to oxidation, to hydrolysis, or to other kinds of spoiling which affect the quality and the effectiveness of the substance. One way of increasing lifetime and of avoiding problems associated with the chemical instabilities of such compounds and/or with storage conditions is to store them in the form of a powder and then make up a solution with a solvent immediately before administering the substance. This type of device is particularly suitable for treatment via the nose.
Documents EP-0 606 672 and EP-0 562 943 disclose devices each having a tank filled with liquid, a tank filled with powder, and a pump for dispensing a solution made by mixing those two substances. Prior to use, the powder is mixed with the liquid and then the liquid is dispensed in selective manner by means of the pump. Those devices present various drawbacks. Their structure does not enable the powder tank and the liquid tank to be filled and/or stored separately, thus making it impossible in particular to use freeze-drying for the powder tank. Unfortunately, in particular for devices that are to deliver a small number of doses, the accuracy of dosage can be considerably improved by filling the powder tank with a pre-dosed liquid solution and then freeze-drying the tank of solution. The fact that the two tanks cannot be stored separately also constitutes a drawback from the point of view of storing the device prior to use.
Certain documents, e.g. U.S. Pat. No. 3,946,743, U.S. Pat. No. 5,380,281, and U.S. Pat. No. 5,569,191 disclose dispenser devices such as syringes that are suitable for mixing together a powder and a liquid prior to dispensing the mixture. In those documents, the mixing process is implemented by means of a needle which pierces the stopper(s) closing the tanks in order to put them into communication. That implementation suffers from the drawback that while the membrane or gasket is being pierced, particles of the material constituting the membrane or the gasket run the risk of becoming mixed in with the fluid that is to be dispensed. This can pollute or contaminate the substance or can block the outlet channel during dispensing.
An object of the present invention is to provide a device for dispensing a fluid which does not suffer from the above drawbacks.
Another object of the present invention is to provide a device for dispensing a fluid which is simple and of low cost to manufacture and use.
Another object of the present invention is to provide such a device for spraying a solution that is made up extemporaneously, where the powder tank is made, filled, and/or stored separately from the liquid tank. In particular, an object of the present invention is to provide such a device which makes it possible to determine the dose in the powder tank by freeze-drying a pre-dosed liquid solution.
Another object of the present invention is to provide a device for dispensing a fluid in which a full dose of substance is dispensed on each actuation by proper spraying, in particular with nasal type uses.
A further object of the invention is to provide a device for spraying a fluid obtained by previously mixing together two different substances, in which the mixing process avoids any risk of the fluid for spraying becoming polluted or contaminated, and avoids any risk of the outlet channel becoming blocked.
The present invention thus provides a fluid spray device comprising an outlet channel terminating in a spray orifice, a first tank containing a first substance, a second tank containing a second substance, said two tanks being interconnected by a passage and, prior to actuation of the device, being separated from each other in leakproof manner by sealing means disposed in said passage, mixer means being provided to open said passage and to mix together the two substances before they are dispensed, and dispenser means being provided for dispensing said mixture, said mixer means comprising a first piston slidably received in one of the tanks to transfer one of the substances from its tank into the other tank, said dispenser means including a second piston slidably received in the other tank for dispensing the mixture of the two substances via the outlet channel, the device being characterized in that said sealing means comprise at least one ball adapted to be expelled from the passage by the pressure created in one of the tanks when said first piston is actuated.
Advantageously, said mixer means comprise a hollow rod secured to the first piston and adapted to penetrate into said passage to expel the balls and, after the two substances have been mixed together, extending to the second tank in such a manner that said hollow rod forms the inlet end of the outlet channel.
Preferably, said mixer means are actuated independently of said dispenser means.
In a preferred variant, said dispenser means are adapted to dispense the entire mixture of the two substances in a single actuation.
In another variant, said dispenser means include or co-operate with stop means for subdividing the mixture of the two substances into a plurality of doses, one dose being dispensed on each actuation.
In an advantageous embodiment of the invention, the device comprises two independent subassemblies, the first subassembly having the outlet channel, the first tank, and one of the pistons, and the second subassembly having the second tank and the other piston, connection means being provided for connecting the two subassemblies together.
Advantageously, each of the first and second tanks has a respective ball expelled during actuation of the mixer means.
In another embodiment of the invention, the mixer means comprise the piston disposed in the second tank, actuation of said piston creating sufficient pressure in the second tank to expel the ball from the passage into the inside of the first tank and to transfer the substance contained in the second tank into the first tank to mix therein with the other substance, the dispenser means including the piston disposed in the first tank, with actuation thereof serving to dispense the mixture.
Preferably, one of the substances is a liquid and the other substance is a powder, mixing being performed extemporaneously by transferring the liquid into the tank containing the powder.
Advantageously, said first tank contains a solvent and said second tank contains a powder, or vice versa.
Preferably, said powder is a pre-dosed liquid solution that has subsequently being freeze-dried.